Technical Field
The present invention generally relates to cell sensors, and more particularly to devices and methods for sensing cell activity using electrochemical feedback.
Description of the Related Art
Cells are commonly grown in a lab on dishes or in wells that contain nutrients in the form of fluid, gel or solids. These may be human or animal cells, as well as microorganisms, such as bacteria, fungi, archaea and eukaryotic parasites used in research or clinical diagnostics and therapeutics. Cells are typically grown in an incubator with controlled temperature and humidity. To determine the degree of growth of cells, the cells are most often monitored visually by a human. For example, samples from potential infection sites in patients are inoculated on a Petri dish and a lab technician may visually inspect the dish after a few hours to a few days to spot signs of bacterial colony formation. This is labor intensive and also is associated with a risk for contamination. When cells require a strict anaerobic environment, visually inspecting the cells entails exposing them (even if for a limited period of time) to air, which may delay their growth or lead to their death.
Visual inspection is widely used to determine bacterial susceptibility to antibiotics, for example, using a disc-diffusion test, wherein bacterial growth is inhibited around a disc containing an antibiotic drug. However, it is practically impossible for humans to continuously monitor cells in a culture. Moreover, for microorganism growth to be visually evident to the naked eye takes an extremely high number of cells to be accumulated.